Howdy Aaron,
Welcome to our support forums and thanks for reaching out to us. I can help you here 🙂
First of all, Have you downloaded and installed Events Calendar PRO? If not please check out this guide walking you through the process → New User Primer: The Events Calendar and Events Calendar PRO. If you don’t have PRO installed, you’ll only see a slot to enter the Event Aggregator license, which might cause this problem.
Once PRO is installed and active you should see another license field to input the PRO license.
If this is already correctly configured but still not working please send me a screenshot of the license page (mark reply as private).
Thanks,
Nico